CSS and JS minification with django-pipeline

JS and CSS minification

Not only minification:

pipeline creates unique names for script files like: /static/css/weblog.min.c79c5280748b.css, so no need to change file ?version
it glues files, so it reduces files count
it makes templates simpler because of inclusions moved to settings file
it automatically converts less/sass to css while development

5 steps to install and configure django-pipeline:

CSS and JS minification with django-pipeline

Step 1 (install pipeline)

requirements.txt:

django-pipeline

settings.py:

INSTALLED_APPS += ('pipeline',)
STATICFILES_STORAGE = 'pipeline.storage.PipelineCachedStorage'

For settings I use directory based module, very usefull practice:

- project
    - settings
        - __init__.py
        - admins.py
        - apps.py
        - pipeline.py
        ...
    ...

Don't forget to include all settings files in __init__.py:

from .admins import *
from .pipeline import *
...

Step 2 (configure pipeline)

As example, pipeline.py:

PIPELINE_CSS = {
    'bootstrap': {
        'source_filenames': (
            'css/bootstrap.less',
        ),
        'output_filename': 'css/bootstrap.min.css',
    },
    'weblog': {
        'source_filenames': (
            'css/common.less',
            'libs/prettify/prettify.css',
            'css/weblog.less',
        ),
        'output_filename': 'css/weblog.min.css',
    },
    'flatpages': {
        'source_filenames': (
            'css/common.less',
            'css/flatpages.less',
        ),
        'output_filename': 'css/flatpages.min.css',
    }
}

PIPELINE_JS = {
    'jquery': {
        'source_filenames': (
            'js/jquery.min.js',
        ),
        'output_filename': 'js/jquery.min.js',
    },
    'weblog': {
        'source_filenames': (
            'js/jquery.validate.js',
            'libs/prettify/prettify.js',
            'js/weblog.js',
        ),
        'output_filename': 'js/weblog.min.js',
    },
    'flatpages': {
        'source_filenames': (
            'js/flatpages.js',
        ),
        'output_filename': 'js/flatpages.min.js',
    },
}

# When PIPELINE is True, CSS and JavaScripts will be concatenated and filtered.
# When False, the source-files will be used instead.
# Default: PIPELINE = not DEBUG

PIPELINE_CSS_COMPRESSOR = 'pipeline.compressors.yui.YUICompressor'
PIPELINE_JS_COMPRESSOR = 'pipeline.compressors.yui.YUICompressor'

PIPELINE_YUI_BINARY = '/usr/bin/yui-compressor'

PIPELINE_COMPILERS = (
  'project.apps.core.compilers.RubyLesscCompiler',
)

PIPELINE_LESS_BINARY = '/usr/local/bin/lessc'

PIPELINE_DISABLE_WRAPPER = True

Step 3 (install lessc and yui-compressor binary)

! See UPD beneath.

Tested on Debian 6 and ubuntu 12.10.

Install lessc (I use lessc wrote in ruby instead if java version):

sudo apt-get install rubygems1.8 ruby1.8-dev
sudo gem install rubygems-update
sudo gem update rubygems
sudo gem install less
sudo ln -s /var/lib/gems/1.8/bin/lessc /usr/bin/

Additionally for Debian:

sudo gem install therubyracer

Install yui-compressor:

sudo apt-get install yui-compressor

Step 4 (is it works?)

lessc wrote in ruby has some differences in command line parameters statement, so we have to implement compiler class for it and add this class to PIPELINE_COMPILERS:

# project/apps/core/compilers.py
from os.path import dirname

from pipeline.conf import settings
from pipeline.compilers import SubProcessCompiler


class RubyLesscCompiler(SubProcessCompiler):
    output_extension = 'css'

    def match_file(self, filename):
        return filename.endswith('.less')

    def compile_file(self, infile, outfile, outdated=False, force=False):
        command = "%s %s %s > %s" % (
            settings.PIPELINE_LESS_BINARY,
            settings.PIPELINE_LESS_ARGUMENTS,
            infile,
            outfile
        )
        return self.execute_command(command, cwd=dirname(infile))

Check paths to binaries are right:

PIPELINE_YUI_BINARY = '/usr/bin/yui-compressor'
PIPELINE_LESS_BINARY = '/usr/local/bin/lessc'

and fix them or create symbolic links.

To test all works fine, run:

manage.py collectstatic

On every change in .less files will generated file with same name but with .css extension, so we don't need to use less.js.
I don't think You need to have automatically generated css files under version control, so just add them to .gitignore.

Step 5 (templates)

Load compressed template tag module and add compressed_css and compressed_js to include css/js files to page:

{% load compressed %}

{% block css %}
    {{ block.super }}
    {% compressed_css 'weblog' %}
{% endblock %}

{% block js %}
    {{ block.super }}
    {% compressed_js 'jquery' %}
    {% compressed_js 'weblog' %}
{% endblock %}

Links:

UPD 2014-04-02

less processor

Use less from node.js packages (npm install less) instead of ruby version.

Licensed under CC BY-SA 3.0